The long term goal of this research proposal is to understand the role of cadherin 5, an endothelial specific cadherin. Cad5 is expressed at the endothelial cell junctions, and is more highly expressed at cell-cell contact points. Some preliminary experiments revealed that when a wound is induced in an endothelial cell monolayer, the cells are incubated in the presence of cad5 mAb, they actually grow back faster than the untreated monolayer. Based on the preliminary findings, the role of cad5 will be investigated using other block agents to inhibit cad5 function. Polyclonal antibodies to the human cad5 will be generated block other domains of cad5. Additional mAbs to cad5 will be made, to generate mAbs that will recognize different epitopes of cad5. The extracellular portion of human cad5 cDNA will be linked to human IgG in a expression vector, and transfected into cells to produce soluble recombinant cad5-IgG fusion protein. This will additionally be used as a blocking agent, to mimic the homophilic binding of cad5 to itself, the mode of binding preferred by cadherins in general. After testing migration of cells in the wounding experiments with the various reagents, the role of the murine cad5 will be studied in vivo by injecting Matrigel containing bFGF and heparin to induce angiogenesis, along with various cad5 antibodies, into mice. In order to accomplish this, the murine cad5 cDNA will be cloned, and stably expressed in cell lines. Antibodies to the murine cad5, both polyclonal and monoclonal, will be generated. Additionally, the soluble recombinant cad5-IgG will be constructed for the mouse as well as, to dissect the role of cad5 by blocking with different agents, which block different domains of cad5. This will provide information on the functional significance of the various domains of cad5 in angiogenesis.